When a document is copied with the use of a conventional image forming apparatus, for example, a color copying machine, a formed image slightly differs from the original image in quality due to the machine's features. When another copy is made from a photocopy of the original document, the difference becomes more significant. Therefore, when the image on the original document and the image formed by the latest copying operation after subsequent copying are compared, there are differences between the two images in color quality and balance if they are color copies or in the thickness of letters and lines if they are black-and-white copies. The differences become greater as the number of times performing subsequent copying increases. To overcome such a problem, for example, a color copy is produced from an original color document by adjusting the color-balance in accordance with the tone of the original document. If there is a need to keep conditions for producing copies of a good color-balance with respect to a document, the conditions are stored in a memory in the main body of the color copying machine. So, when copying the document again, the copying conditions are read from the memory and set by depressing the memory key on the operation panel so as to make copies in accordance with the conditions.
With the apparatus, however, such conditions must be stored in the memory by the user, thereby causing the user to undertake time-consuming tasks.
Moreover, the user must remember which document corresponds to which copying conditions stored. This not only causes the user trouble, but may also produce copies depending on erroneous conditions due to the user's incorrect memory or changes in the content of memory made by someone else.